Schlafen schlafen

I've been having a strange relationship with sleep recently. Today, for example, I have overslept a class by 4 hours. And it's not that the class was early. I had to wake up at 10 and woke up at 2 instead... I have also tried some alternative sleeping patterns to aid memorization, but, again, ended up sleeping 12 hours instead of 7. Getting up has become a terrible chore. It has never been easy but now! Can it be all the caffeine that used to circulate in my blood?